KENDRAPARA: Large numbers of endangered Olive Ridley sea turtles have started arriving at three major rookeries - Devi river mouth , Rushikulya river mouth and Gahirmatha marine sanctuary. As the turtles are mating in sea waters, the Forest and Coast Guard officials have remained on high alert. To protect the marine species, the Forest Department have established hatcheries at Aagarnasi, Pentha and Babubali within Gahirmatha and Jahania and Sarana beaches within Devi river mouth. All the hatcheries are covered with plastic nets to prevent the entry of predators, said Prasan Behera, Divisional Forest Officer of Bhitarkanika National Park. The mass nesting or arribadda of the turtles would start within two months, said sources . Last year about 3.5 lakh turtles laid eggs on Gahirmatha beach within Gahirmatha Marine Sanctuary, said the forest officer. The Forest Department recently requested the officials of Defence Research and Development Organisation (DRDO) to switch off bright lights on the missile test range at Wheelers island to facilitate mass nesting of the turtles at Gahirmatha, sources said. Despite all the protection, large number of turtles are being killed as the fishing trawlers are not using TED (Turtle Excluder Device). As per the Orissa Marine Fishing Regulation Act,1982, the use of TED is mandatory for all the trawlers, said Sudhanshu Parida, environmentalist and secretary of district unit of People for Animals. The forest officials have established 15 turtle protection camps, including three camps on the sea, and deployed forest guards to protect the turtles. The Coast Guard officials have also deployed two ships at Gahirmatha to protect the marine species under Operation Olive, said a senior official of Coast Guard, Paradip.